The invention relates to a tank for the storage of a liquid with a device for feeding one or more substances thixotroping the liquid to the liquid in the tank. Such tanks are used in the chemical industry when liquids are to be solidified by the addition of a suitable agent (thixotropy) without any major temperature variation being required as in the case of solidification by freezing. A 2-component adhesive is similarly solidified, for example, but in this case the solidifying component is a hardener which gives rise to a generally irreversible solidification as a result of a chemical reaction with the first component, whilst in thixotropy solidification is caused by physical interaction of the components, which can also be reversed (re-liquefaction). DE 37 06 860 C2, for example, describes a thixotropic preparation using highly dispersive silicon oxide.
The handling of liquids in daily life may be associated with different risks. For example, an accident during the transport of dangerous liquid goods generally results in the dangerous goods escaping from the tank, and diversely contaminating the environment over a large area. In the case of combustible liquids an explosive flame may develop. DE 28 13 449 A1 discloses a device for sealing leakage points on tanks in which the medium escaping from the leakage point is solidified by means of a coolant by freezing the medium. However, the medium to be solidified must in this case be cooled to below its melting temperature. A thixotropy, i.e. rapid solidification of the dangerous liquids, could in such emergencies contribute to preventing disasters. The same also applies to the prevention of a fire or explosion of a fuel tank in vehicles which have been involved in an accident or to the prevention of environmental damage in the event of damage to a tanker at sea. A further example that could be mentioned is the accidental leakage from a slurry tank and the resultant environmental pollution.
Here too a more serious disaster could be avoided with the targeted initiation of a thixotropic “reaction”. Even in the case of intrinsically harmless liquids, such as beer or wine, in a drink cellar, it may possibly be advantageous to prevent undesirable escape in large quantities from the container concerned, for example a barrel or tank, quickly and effectively.
It is therefore the underlying object of this invention to modify a tank of the type already described with the simplest possible agents so that the liquid contained in it is prevented from being discharged or from escaping under certain defined circumstances.